package usaco.c2009.march.silver;

import java.util.Arrays;
import java.util.Scanner;

/*
 * p3207
 * USACO 2009 March - Silver
 * Hint: Sort two lists and match A_i with B_i.
 */

public class p3207 {

	static int N, X, Y, cost;
	static int[] A, B;

	public static void main(String[] args) {
		
		Scanner scanner = new Scanner(System.in);
		N = scanner.nextInt();
		X = scanner.nextInt();
		Y = scanner.nextInt();
		A = new int[N];
		B = new int[N];
		for (int i=0;i<N;++i) {
			A[i] = scanner.nextInt();
			B[i] = scanner.nextInt();
		}
		Arrays.sort(A);
		Arrays.sort(B);
		for (int i=0;i<N;++i) {
			if (A[i] < B[i]) {
				cost += X * (B[i] - A[i]);
			}
			else {
				cost += Y * (A[i] - B[i]);
			}
		}
		System.out.println(cost);
		
	}

}
